It is well known in the art to produce an abrading tool which comprises a metal substrate and having hard carbide particles fixedly adhered thereto by utilizing a metal matrix. Examples of such tools, and methods for making such tools are shown in the U.S. Pat. No. 3,868,235 to Held and the U.S. Pat. No. 3,378,361 to Harris, Jr.
Commonly, these tools need to be finally finished or dressed to exacting surface configurations in order for the tool to accurately grind or abrade a workpiece. Typically, the dressing operation is carried out by utilizing an electrical discharge machining (EDM) technique. Alternatively, superabrasive dressing wheels, such as diamond wheels, may be used to dress the tool in order to bring them within the specific surface configurations. During the dressing process, the surface of the carbide particles on the tool are rendered relatively smoother than when originally applied and some of the abrasiveness of the carbide particles is therefore, lost. Another deficiency is that the cemented carbide particles are relatively harder than the matrix material. Therefore, the matrix material may wear away at a faster rate than the carbide particles causing the carbide particles to become loose and perhaps fall out of the matrix.
The U.S. Pat. No. 4,505,720 to Gabor et al. issued Mar. 19, 1985 shows a silicone carbide particle having a surface layer of a hard refractory material such as silicone nitride or carbide, titanium nitride or carbide, sialone, or other similar refractory material. Each silicone carbide particle is at least partially coated with the hard refractory material. The coated particles are then secured onto an abrasive disk for use as an abrading tool.
The U.S. Pat. No. 4,868,069 to Darrow issued Sep. 19, 1989 discloses a grinding wheel having a steel substrate metallurgically bonded to a coating of nickel or cobalt. Abrasion resistant tungsten carbide or titanium carbide grit particles protrude from the coating of the nickel or cobalt. The coating acts as a bonding agent between the steel substrate and the grit particles. The coating or bonding agent comprises a nickel or cobalt coating which is hardened by adding boride, carbide, nitride, or carbon nitride using conventional techniques. The titanium carbide grit particles remain unaffected by the hardening treatment of the coating.